The work proposed here develops detailed inquiries into three closely related problems of general importance in sickle cell anemia. The principal goals of this work include (1) locating critical intermolecular bonding sites on the sickle hemoglobin molecule, along with determining the types of interactions which initiate the hemoglobin S aggregation process and stabilize the aggregate structure, (2) determining the role of erythrocyte membrane structural proteins in the formation of irreversibly sickled cells, and (3) the development of liposome encapsulation as a method for transporting lipid-insoluble antisickling reagents across the erythrocyte membrane. The systematic design of aggregation inhibitors requires a detailed understanding of the intermolecular binding sites and the types of interactions which produce aggregation. We propose to investigate this problem, primaily utilizing the methods of conventional and saturation transfer electron spin resonance, proton-enhanced 13C nuclear magnetic resonance and spin label induced nuclear magnetic resonance relaxation to permit detailed studies at a molecular level. These methods will be used to study the structure of the aggregated hemoglobin fibers and the nucleation process which appears to initiate aggregation, and to determine the detailed binding geometries of several small molecules which appear to exhibit site-specific inhibitory activity. The formation of irreversibly sickled cells is approached through basic molecular studies of the mechanisms by which structural protens of the erythrocyte membrane regulate membrane flexibility. Liposome composition and solution ionic conditions are varied to optimize incorporation into erythrocytes.